Data pad region of liquid crystal display panel and fabricating method thereof

ABSTRACT

A data pad region of a liquid crystal display panel includes a plurality of data lines vertically arranged at specified intervals, a plurality of data pads respectively connected to the data lines, at least one first side contact with a first area formed in each data pad and at least one second side contact with a second area formed in each data pad, wherein the first area is larger than the second area.

[0001] This application claims the benefit of Korean Application No.P2002-085593 filed in Korea on Dec. 27, 2002, which is herebyincorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a data pad region of a liquidcrystal display panel and a fabricating method thereof, and inparticular to a data pad region of a liquid crystal display panel and afabricating method thereof for preventing damage to a data pad regionand for securing an electrical contact area.

[0004] 2. Discussion of the Related Art

[0005] In general, a liquid crystal display device displays a desiredimage by individually supplying a data signal to liquid crystal cellsarranged in a matrix form and controlling light transmittance of theliquid crystal cells according to image information. The liquid crystaldisplay device includes a liquid crystal display panel with the liquidcrystal cells arranged in a matrix form and a driving unit for drivingthe liquid crystal cells in each of the liquid crystal cells. The liquidcrystal display panel includes a color filter substrate and a thin filmtransistor array substrate attached with a space therebetween, and aliquid crystal layer formed within the space between the color filtersubstrate and the thin film transistor array substrate.

[0006] A common electrode and a pixel electrode are formed facing eachother on inner surfaces of the color filter substrate and the thin filmtransistor array substrate such that an electric field can be applied tothe liquid crystal layer. The pixel electrode is formed in every liquidcrystal cell of the thin film transistor array substrate, while thecommon electrode is integrally formed at the entire surface of the colorfilter substrate. By controlling a voltage applied to the pixelelectrode while the common electrode is receiving another voltage, lighttransmittance of liquid crystal cells can be individually controlled. Tocontrol the voltage applied to the pixel electrode by liquid crystalcells, each liquid crystal cell includes a thin film transistor used asa switching device. On the thin film transistor array substrate of theliquid crystal display panel, a plurality of data lines for transmittingimage information from a data driving unit to the liquid crystal cellsand a plurality of gate lines for transmitting a scan signal from a gatedriving unit to the liquid crystal cells intersect to define liquidcrystal cells that are adjacent to every intersection of the data linesand gate lines. The gate driving unit sequentially supplies a scansignal to the gate lines, so that gate lines of liquid crystal cellsarranged in the matrix can be selected one by one while imageinformation is supplied to a selected line of the liquid crystal cellsfrom the data driving unit by way of the data lines. Parts of the liquidcrystal display device will be described in detail with reference toaccompanying drawings.

[0007]FIG. 1 is a plan view illustrating a unit pixel of liquid crystaldisplay device in accordance with a related art. As shown in FIG. 1,gate lines 4-1 and 4 are horizontally arranged at regular intervals, anddata lines 2 and 2+1 are vertically arranged at regular intervals.Accordingly, the gate lines 4-1 and 4 and the data lines 2 and 2+1 crosseach other. A unit pixel is defined within the rectangular region formedby the crossing gate lines 4-1 and 4 and data lines 2 and 2+1. The unitpixel includes a thin film transistor (TFT) and a pixel electrode 14.

[0008] The thin film transistor (TFT) includes a gate electrode 10extending from the gate line 4; a source electrode 8 extending from thedata line 2 so as to be partly overlapping with the gate electrode 10;and a drain electrode 12 that corresponds to the source electrode 8across from the gate electrode 10. The source electrode 8 and the drainelectrode 12 are formed over the gate electrode 10 so as to beseparated. The drain electrode 12 is electrically connected to a pixelelectrode 14 through a drain contact hole 16. The pixel electrode 14 ismade of a transparent conductive material such as indium tin oxide (ITO)or indium zinc oxide (IZO).

[0009] In addition, the thin film transistor (TFT) includes asemiconductor layer (not shown) that becomes a conductive channelbetween the source electrode 8 and the drain electrode 12 when a scansignal is supplied to the gate electrode 10. The scan signal is suppliedto the gate electrode 10 from the gate line 4. When the conductivechannel is formed between the source electrode 8 and the drain electrode12 of the thin film transistor (TFT), a data signal supplied to thesource electrode 8 from the data line 2 is transmitted to the drainelectrode 12 via the conductive channel.

[0010] Because the drain electrode 12 is electrically connected to thepixel electrode 14 through the drain contact hole 16, the data signalsupplied to the drain electrode 12 is applied to the pixel electrode 14.Thus, the pixel electrode 14 receives the data signal and generates anelectric field across the liquid crystal layer with a common electrode(not shown) formed on a color filter substrate. When the electric fieldis applied to the liquid crystal layer, the liquid crystal is rotated bydielectric anisotropy and transmits light from a back light. Thepolarization of transmitted light is adjusted by a voltage value of thedata signal.

[0011] The pixel electrode 14 also contacts to a storage electrode 20through a storage contact hole 22. The storage electrode 20 is operatedas a storage capacitor 18 by being overlapped with a preceding gate line4-1 with a gate insulating layer (not shown) therebetween. Accordingly,the storage capacitor 18 charges to a voltage value of the data signalfor a turn-on period of the thin film transistor (TFT) in which the scansignal is applied to the gate line 4. Afterward, the storage capacitor18 supplies the charged voltage to the pixel electrode 14 during aturn-off period of the thin film transistor (TFT) such that operation ofthe liquid crystal is maintained.

[0012]FIG. 2 is an exemplary view illustrating a section of a unit pixeltaken along a line I-I′ in FIG. 1. As shown in FIG. 2, the liquidcrystal display panel includes a color filter substrate 60 and a thinfilm transistor array substrate 50 attached with a space maintainedtherebetween by a spacer 70. A liquid crystal layer 80 is positionedwithin the space between the thin film transistor array substrate 50 andthe color filter substrate 60.

[0013] Fabrication processes of a thin film transistor will be describedwith reference to FIG. 2. First, a gate electrode 10 is formed byapplying metal material on the thin film transistor array substrate 50and pattering the metal material. Then, a gate insulating layer 30 isformed by depositing an insulating material at an upper surface of thethin film transistor array substrate 50 on which the gate electrode 10is formed. An active layer 36 is formed on the gate insulating layer 30by sequentially depositing a semiconductor layer 32 made of amorphoussilicon and an ohmic contact layer 34 made of n+ amorphous silicon dopedwith phosphorus (P) at high concentration and patterning thesemiconductor layer 32 and the ohmic contact layer 34. By depositingmetal material on the gate insulating layer 30 and the ohmic contactlayer 34 and patterning the metal material, the source electrode 8 andthe drain electrode 12 of the thin film transistor (TFT) are formed. Thesource electrode 8 and the drain electrode 12 are patterned so as to beseparated on the surface of the active layer 36.

[0014] The ohmic contact layer 34 is exposed on the surface of theactive layer 36 between the source electrode 8 and the drain electrode12. The exposed ohmic contact layer 34 is removed in the patterningprocess of the source electrode 8 and the drain electrode 12.Subsequently, semiconductor layer 32 is exposed between the sourceelectrode 8 and the drain electrode 12 by removing the ohmic contactlayer 34, and the exposed semiconductor layer 32 is a channel region ofthe thin film transistor (TFT).

[0015] A passivation film 38 is then formed by depositing an insulatingmaterial on the gate insulating layer 30 on which the source electrode 8and the drain electrode 12 were formed including the exposedsemiconductor layer 32. A drain contact hole 16 exposing a portion ofthe drain electrode 12 is formed by selectively etching a portion of thepassivation film 38 on the drain electrode 12. By forming a transparentelectrode material on the passivation film 38 and patterning thetransparent electrode material, the pixel electrode 14 is formed so asto be connected to the drain electrode 12 through the drain contact hole16.

[0016] After forming an aligning layer 51 on the surface of theresultant structure, a rubbing process is performed. More particularly,the surface of the aligning layer 51 is rubbed by a fabric at a uniformpressure and speed. High molecule chains on the surface of the aligninglayer 51 are aligned in a specified direction. This determines aninitial aligning direction of the liquid crystal.

[0017] Fabrication processes of the storage capacitor region will now bedescribed with reference to accompanying FIG. 2. First, the gate line4-1 is patterned on the thin film transistor array substrate 50, and thegate insulating layer 30 is formed thereon. The gate line 4-1 is formedwhile the gate electrode 10 of the thin film transistor (TFT) is formed.The gate insulating layer 30 is the same as the gate insulating layer 30of the thin film transistor (TFT). The storage electrode 20 is patternedon the surface of the gate insulating layer 30. The storage electrode 20is formed while forming of the source electrode 8 and the drainelectrode 12 of the thin film transistor (TFT), and operated as thestorage capacitor 18 by being overlapped with a portion of the gate line4-1 with the gate insulating layer 30 therebetween.

[0018] After forming the passivation film 38 on the gate insulatinglayer 30 and the storage electrode 20, a storage contact hole 22 isformed exposing a portion of the storage electrode 20 by etching aportion of the passivation film 38. The passivation film 38 is the sameas the passivation film 38 in the thin film transistor (TFT) region, andthe storage contact hole 22 is formed while forming the drain contacthole 16 of the thin film transistor (TFT). The pixel electrode 14 isthen patterned on the passivation film 38, and connected to the storageelectrode 20 through the storage contact hole 22. The pixel electrode 14is the same as the pixel electrode 14 formed on the thin film transistor(TFT) region.

[0019] Fabrication processes of the color filter substrate 60 will bedescribed with reference to FIG. 2. First, a black matrix 62 is coatedon the color filter substrate 60 with specified intervals. A red (R),green (G) and blue (B) color filter 63 is formed on the surface of thecolor filter substrate 50 on which the black matrix 62 is formed. Acommon electrode 64 is formed by forming a metal material on the surfaceof the color filter 63 including the black matrix 62 and patterning themetal material.

[0020] After forming an aligning layer 65 on the surface of theresultant structure, a rubbing process is performed. After the thin filmtransistor array substrate 50 and the color filter substrate 60 isfabricated, a sealant (not shown) is formed on the thin film transistorarray substrate 50, and a spacer 70 is formed on the color filtersubstrate 60. The spacer 70 can be formed on the thin film transistorarray substrate 50 and the sealant can be formed on the color filtersubstrate 60. The spacer 70 can be positioned by a scattering method,such as scattering glass beads or plastic beads having a certaindiameter.

[0021] After forming the sealant and the spacer 70, the thin filmtransistor array substrate 50 and the color filter substrate 60 areattached to each other. The attached thin film transistor arraysubstrate 50 and the color filter 60 are cut into unit liquid crystaldisplay panels. To improve the yield, plural liquid crystal displaypanels are simultaneously formed on a large-sized glass substrate. Thus,a cutting process is required.

[0022] A liquid crystal layer 80 is formed within a space between thealigning layer 51 of the thin film transistor array substrate 50 and thealigning layer 65 of the color filter substrate 60 by injecting liquidcrystal into the cut unit liquid crystal panel and sealing an injectionhole. After injecting liquid crystal into plural liquid crystal panels,the attached thin film transistor array substrate 50 and color filtersubstrate 60 are cut into unit liquid crystal panels. However, due tothe increased size of a unit liquid crystal panel, it is difficult toperform a process for injecting liquid crystal uniformly.

[0023] Productivity may be lowered due to liquid crystal injectiondefect. Accordingly a method of injecting liquid crystal after theattached thin film transistor array substrate 50 and color filtersubstrate 60 that is cut into unit liquid crystal panels has beenproposed. Since the unit liquid crystal panel has only a few μm(microns) of cell gap for the hundreds of cm² area, a vacuum injectionmethod is most frequently used, which uses a pressure difference betweenan inner side and an outer side of the unit liquid crystal panel, inorder to effectively inject the liquid crystal thereto.

[0024]FIG. 3 is an exemplary view illustrating a section of a unit pixeltaken along a line II-II′ in FIG. 1. FIG. 3 shows the gate insulatinglayer 30 formed on the surface of the thin film transistor arraysubstrate 50; the data lines 2 and 2+1 patterned on the surface of thegate insulating layer 30 so as to be separated from each other; thepassivation film 38 formed on the surface of the gate insulating layer30 including the data lines 2 and 2+1; and the pixel electrode 14patterned on the surface of the passivation film 38 in which the datalines 2 and 2+1 are separated. Although not shown in FIG. 3, asdescribed in the thin film transistor (TFT) fabrication processes withregard to FIG. 2, the active layer 36 including the semiconductor layer32 and the ohmic contact layer 34 may be remained on the lower portionof the data lines 2 and 2+1. Usually, the passivation film 38 is made ofan inorganic thin film, such as SiNx or SiOx, etc.

[0025] By overlapping the data lines 2 and 2+1 with a portion of thepixel electrode 14 by the passivation film 38, an aperture ratio of theliquid crystal display device can be further improved. However, becausethe passivation film 38 is made of a thin film inorganic material, suchas SiNx or SiOx, when the data lines 2 and 2+1 are overlapped with aportion of the pixel electrode 14 by the passivation film 38, signalcharacteristics are deteriorated because the data lines 2 and 2+1 andthe pixel electrode 14 are influenced mutually (for example, parasiticcapacitance). To prevent deterioration of the signal characteristics incase that the data lines 2 and 2+1 and the pixel electrode 14 areoverlapped with a portion to each other by the passivation film 38, ahigh aperture ratio liquid crystal display device using thick filmorganic material such as BCB (benzocyclobutene), etc. having lowdielectric constant for a material of the passivation film 38 has beensuggested. The high aperture ratio liquid crystal display device will bedescribed with reference to accompanying drawings.

[0026]FIG. 4 is an exemplary view illustrating a plan view of the highaperture ratio liquid crystal display device, and FIG. 5 is an exemplaryview illustrating a section taken along a line III-III′ in FIG. 4.First, FIG. 4 has the same plan construction with FIG. 1, except for theoverlapping of a portion of the pixel electrode 14 with the data lines 2and 2+1. FIG. 5 shows the gate insulating layer 30 formed on the surfaceof the thin film transistor array substrate 50; the data lines 2 and 2+1patterned on the surface of the gate insulating layer 30 so as to beseparated from each other; the passivation film 48 formed on the surfaceof the gate insulating layer 30 including the data lines 2 and 2+1; andthe pixel electrode 14 patterned on the surface of the passivation film38 in which the data lines 2 and 2+1 are separated so as to be partlyoverlapped with the data lines 2 and 2+1. Although not shown in FIG. 5,as described in the thin film transistor fabrication processes in FIG.2, the active layer 36 including the semiconductor layer 32 and theohmic contact layer 34 may be remained on the lower portion of the datalines 2 and 2+1. By forming the passivation film 48 as a thick film byusing an organic material such as BCB, etc. having low dielectricconstant, although the data lines 2 and 2+1 are overlapped with aportion of the pixel electrode 14, it is possible to prevent theoccurrence of mutual influence in the overlapped regions of the pixelelectrode 14.

[0027]FIG. 6 is an exemplary view illustrating a schematic planstructure of the unit liquid crystal display panel. As shown in FIG. 6,a unit liquid crystal display panel 100 is constructed by attaching thethin film transistor array substrate 50 to the color filter substrate60, an upper longer side and a left shorter side of the thin filmtransistor array substrate 50 protrude with respect to the color filtersubstrate 60. The unit liquid crystal display panel 100 includes animage display region 113 on which the gate lines and the data linescross each other. The unit pixels are arranged in a matrix form. A gatepad region 114 is connected to the gate lines of the image displayregion 113. The data pad region 115 is connected to the data lines ofthe image display region 113.

[0028] The thin film transistor array substrate 50 and the color filtersubstrate 60 are separated from each other by the spacer, and attachedto each other by a seal pattern 116 formed at the periphery of the imagedisplay region 113. The gate pad region 114 is formed at the edge of thethin film transistor substrate 50 in which the shorter side protrudes incomparison with the color filter substrate 60, and the data pad region115 is formed at the edge of the thin film transistor substrate 50 inwhich the longer side protrudes with respect to the color filtersubstrate 60. In addition, the gate pad region 114 supplies scan signalsfrom the gate driver integrated circuit to the gate lines of the imagedisplay region 113. The data pad region 115 supplies image informationfrom the data driver integrated circuit to the data lines of the imagedisplay region 113.

[0029]FIG. 7 is detailed view illustrating a portion of the data padregion 115 in FIG. 6. As shown in FIG. 7, the data pad region includesdata lines 2 and 2+1 that are vertically arranged at regular intervalsand data pads 115A and 115B that are electrically connected to the endof the data lines 2 and 2+1. The data pads 115A and 115B respectivelyinclude side contacts SC1 to SC7 separated from each other at regularintervals.

[0030]FIGS. 8A to 8C are exemplary views sequentially illustrating asection construction of the data pad region 115 taken along a lineIV-IV′ in FIG. 7. As shown in FIG. 8A, the gate insulating layer 30, theactive layer 36, the data line 2 and the passivation film 48 made of anorganic material such as BCB, etc. are sequentially formed on thesurface of the thin film transistor array substrate 50. As depicted inFIG. 2, the gate insulating layer 30, the active layer 36 and the dataline 2 are formed in the fabrication of the thin film transistor (TFT).As depicted in FIGS. 4 and 5, the passivation film 48 made of an organicmaterial such as BCB, etc. is formed to improve an aperture ratio of theliquid crystal display device.

[0031] As shown in FIG. 8B, side contact holes SC1′ to SC7′ are formedby etching the passivation film 48. As described above in reference toFIG. 2, etching of the passivation film 48 is performed simultaneouslyin forming of the drain contact hole 16 for connecting the drainelectrode 12 and the pixel electrode 14 of the thin film transistor(TFT), by a dry etching method. In general, the data line 2 is made of aconductive material such as Cr. However, according to size increase andhigh resolution trends of the liquid crystal display device, a width ofthe data line 2 has to be reduced. However, a reduced width increasesresistance even though quantity of image information transmitted throughthe data line 2 is increasing as display panels become larger. Toimprove image information transmission performance, a conductivematerial, such as Mo, having less resistance than Cr has been recentlyused for the data line 2. However, a conductive material, such as Mo,used for the data line 2 can be etched by the dry etching of thepassivation film 48.

[0032] The data line 2 made of a conductive material such as Mo iselectrically contacted to the pixel electrode 14 at the side of the sidecontact holes SC1′ to SC7′. The more the number of the side contactholes SC1′ to SC7′, the more a contact area of the data line 2 and thepixel electrode 14 can be secured, and accordingly resistance can bereduced. In addition, the active layer 36 formed in fabrication of thethin film transistor (TFT) may be etched by the dry etching of thepassivation film 48. Thus, by etching the data line 2 and the activelayer 36, the gate insulating layer 30 is exposed to the bottom surfaceof the side contact holes SC1′ to SC7′.

[0033] Then, as shown in FIG. 8C, by patterning the pixel electrode 14on the surface of the resultant structure, the pixel electrode 14 iselectrically contacted to the side of the data line 2 through the sidecontacts SC1 to SC7. As described above with reference to FIG. 2,patterning of the pixel electrode 14 is performed simultaneously whilethe patterning of the pixel electrode 14 of a unit pixel, and atransparent conductive material, such as ITO, is applied to the pixelelectrode 14.

[0034] In a subsequent probe inspection, needles are contacted to thedata pad region 115, and a test signal is applied. In more detail, whenthe liquid crystal display panel is fabricated, a probe inspection forinspecting an open defect or a short defect of the gate lines and thedata lines through images displayed on the image display region isperformed by applying test signals to the gate lines and the data linesthrough the gate pad region and the data pad region. However, in therelated art, because the plural side contacts SD1 to SD7 are formed onthe data pad region, contact between the needles and the side contactsSD1 to SD7 can not be performed smoothly.

[0035] More particularly, the data pad region 115 has peaks anddepressions because of the plural side contacts SD1 to SD7. Accordingly,when the needles are in contact, a scratch may occur on the surface ofthe data pad region 115 if a misalignment occurs. This causes a defectin the liquid crystal display panel. Further, replacement of damagedneedles may be required.

[0036] In addition, in the data pad region 115, an inorganic material,such as SiNx or SiOx, used for the gate insulating layer 30 has goodinterfacial adhering characteristics. On the contrary, an organicmaterial such as BCB used for the passivation film 48 has poorinterfacial adhering characteristics. Accordingly the pixel electrode 14can be separated from the organic passivation film 48. Moreparticularly, if an area contacted to the passivation film 48 is widerthan an area contacted to the gate insulating layer 30 exposed to thebottom surface of the side contact holes SC1′ to SC7′, the pixelelectrode 14 may be easily separated from the passivation film 48.

[0037] After the liquid crystal display panel is fabricated, when adefective TAB occurs in a module process for electrically contacting thedata driver integrated circuit to the data pad region 115 by a TAB(tape-automated bonding) method, the defective TAB is detached from thedata pad region 115. Because the pixel electrode 14 is adhered to theTAB, a portion or whole pixel electrode 14 is separated from thepassivation film 48. Accordingly, the data pad region 115 is damaged,and becomes a defect of the liquid crystal display panel. In addition,when the defective TAB is detached from the data pad region 115, thepixel electrode 14 and the passivation film 48 may be separated from theactive layer 36 since the pixel electrode 14 adhered to the defectiveTAB.

[0038] To improve interfacial adhering characteristics of thepassivation film 48 made of an organic material, such as BCB, a triplelayer structure depositing an upper SiNx film/BCB film/lower SiNx filmcan be used as the passivation film 48. However, even in the triplelayer structure, when the defective TAB is detached from the data padregion 115, the pixel electrode 14 and the upper SiNx film may separatefrom the BCB film since the pixel electrode 14 is adhered to thedefective TAB. In addition, the pixel electrode 14, the upper SiNx filmand the BCB film may separate from the lower SiNx. Thus, there is nointerfacial adhering characteristics improvement in the data pad region115 with a triple layer structure.

SUMMARY OF THE INVENTION

[0039] Accordingly, the present invention is directed to a data padregion of a liquid crystal display panel and a fabrication methodthereof that substantially obviate one or more of the problems due tolimitations and disadvantages of the related art.

[0040] An object of the present invention is to provide a data padregion of a liquid crystal display panel and a fabrication methodthereof capable of preventing damage of a data pad region and securingan electrical contact region.

[0041] Additional features and advantages of the invention will be setforth in the description which follows, and in part will be apparentfrom the description, or may be learned by practice of the invention.The objectives and other advantages of the invention will be realizedand attained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

[0042] To achieve these and other advantages and in accordance with thepurpose of the present invention, as embodied and broadly described, adata pad region of a liquid crystal display panel includes a pluralityof data lines vertically arranged at specified intervals, a plurality ofdata pads respectively connected to the data lines, at least one firstside contact with a first area formed in each data pad and at least onesecond side contact with a second area formed in each data pad, whereinthe first area is larger than the second area.

[0043] In another aspect, a method for fabricating a data pad region ofa liquid crystal display panel in accordance with the present inventionincludes: forming a gate insulating layer, data lines and a passivationfilm in a data pad forming region of a substrate; forming at least onefirst side contact hole with a first area at the central region of thedata pad forming region and forming at least two second side contactholes with a second area respectively at both edges of the data padforming region, wherein the first area is larger than the second area;and forming at least one first side contact electrically connecting oneof the data lines to a conductive layer at the first side contact holeand forming at least one second side contact electrically contacting thedata line to the conductive layer at the second side contact hole bypatterning a conductive material.

[0044] In another aspect, a liquid crystal display panel has a substratehaving an image display region with unit pixels arranged in a matrix anda data pad region at the periphery of the image display region, whereinthe data pad region includes: a plurality of data lines verticallyarranged at specified intervals; a plurality of data pads respectivelyconnected to the data lines; at least one first side contact with afirst area formed in each data pad; and at least one second side contactwith a second area formed in each data pad, wherein the first area islarger than the second area.

[0045] It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary andexplanatory and are intended to provide further explanation of theinvention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings, which are included to provide afurther understanding of the invention and are incorporated in andconstitute a part of this specification, illustrate embodiments of theinvention and together with the description serve to explain theprinciples of the invention.

[0047]FIG. 1 is a plan view illustrating a unit pixel of a liquidcrystal display device in accordance with a related art.

[0048]FIG. 2 is an exemplary view illustrating a section of a unit pixeltaken along the line I-I′ in FIG. 1.

[0049]FIG. 3 is an exemplary view illustrating a section of a unit pixeltaken along the line II-II′ in FIG. 1.

[0050]FIG. 4 is an exemplary view illustrating a plan construction of ahigh aperture ratio liquid crystal display device.

[0051]FIG. 5 is an exemplary view illustrating a section taken along theline III-III′ in FIG. 4.

[0052]FIG. 6 is an exemplary view illustrating a schematic planstructure of a unit liquid crystal display panel of the related art.

[0053]FIG. 7 is an exemplary view illustrating a portion of a data padregion in detail in FIG. 6.

[0054]FIGS. 8A to 8C are exemplary views sequentially illustrating asection construction of the data pad region taken along a line IV-IV′ inFIG. 7.

[0055]FIG. 9 is an exemplary view illustrating a section of a data padregion of a liquid crystal display penal in accordance with a firstembodiment of the present invention.

[0056]FIGS. 10A to 10C are exemplary views sequentially illustrating asection construction of the data pad region taken along a line V-V′ inFIG. 9.

[0057]FIG. 11 is an exemplary view illustrating a section of a data padregion of a liquid crystal display penal in accordance with a secondembodiment of the present invention.

[0058]FIG. 12 is an exemplary view illustrating a section of a data padregion of a liquid crystal display penal in accordance with a thirdembodiment of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0059] Reference will now be made in detail to the illustratedembodiments of the present invention, examples of which are illustratedin the accompanying drawings.

[0060]FIG. 9 is an exemplary view illustrating a section of a data padregion of a liquid crystal display penal in accordance with a firstembodiment of the present invention. As shown in FIG. 9, the data padregion of a liquid crystal display panel includes data lines 202 and202+1 that are vertically arranged at specified intervals, and data pads215A and 215B that are electrically connected to the data lines 202 and202+1. A first side contact SC11 is respectively formed at the centralportion of the data pads 215A and 215B, and a plurality of second sidecontacts SC12 to SC15 having an area smaller than that of the first sidecontact SC11 are respectively formed at the top end and the bottom endof the data pads 215A and 215B so as to be separated from each other atspecified intervals. When a defective TAB is detached from the data padregion due to TAB defect in a subsequent module process, the first sidecontact SC11 having a wider area than those of the plurality of the sidecontacts SC12 to SC15 prevents films formed on the data pad region frombeing separated from the data pad region by securing a physical contactarea of the films supporting the data pads 215A and 215B. The pluralityof the second side contacts SC12 to SC15 having a smaller area than thatof the first side contact SC11 prevents an increase in electricalcontact resistance for the data pad region by securing a physicalcontact area of the films supporting the data pads 215A and 215B.

[0061]FIGS. 10A to 10C are cross-sectional views sequentiallyillustrating a section construction of the data pad region taken along aline V-V′ in FIG. 9. As shown in FIG. 10A, a gate insulating layer 230,an active layer 236, a data line 202 and a passivation film 248 made ofan organic material such as BCB are sequentially formed in the data padforming region of a substrate 250. The substrate 250 is a thin filmtransistor array substrate of a liquid crystal display panel to beattached to a color filter substrate. A longer side and a shorter sideof the thin film transistor array substrate are protrudes with respectto the color filter substrate. A gate pad region and a data pad regionare formed on the protruded regions of the substrate 250. The substrate250 includes: an image display region on which the gate lineshorizontally arranged at a regular intervals and the data linesvertically arranged at a regular intervals cross with each other; unitpixels arranged in a matrix; the gate pad region connected to the gatelines of the image display region; and the data pad region connected tothe data lines of the image display region. Thin film transistorstransmit image information to the display region through the data linesof the substrate 250.

[0062] At the same time as the thin film transistor in a unit pixel ofthe substrate 250 is formed, the gate insulating layer 230, the activelayer 236, the data line 202 are simultaneously formed on the data padforming region of the substrate 250. The passivation film 248 made of anorganic material, such as BCB, is formed to improve aperture ratio ofthe liquid crystal display panel.

[0063] As shown in FIG. 10B, a first side contact hole SC11′ is formedat the central portion of the data pad forming region, and a pluralityof the second side contact holes SC12′ to SC15′ having an area smallerthan that of the first side contact hole SC11′ are formed at both sidesof the data pad forming region by etching the passivation film 248. Whenforming a drain contact hole for connecting a drain electrode to a pixelelectrode of the thin film transistor, etching of the passivation film248 is also performed. Because the passivation film 248 is made of anorganic material, such as BCB, a dry etching method is used to etch thepassivation film 248.

[0064] Because of the large size and high resolution trends of theliquid crystal display device, a conductive material, such as Mo, havingless resistance than Cr is used for the data line 202. The conductivematerial, such as Mo, is etched by the dry etching of the passivationfilm 248. The data line 202 made of a conductive material, such as Mo,is electrically contacted to a pixel electrode 214 at the sides of thefirst side contact hole SC11′ and the second side contact holes SC12′ toSC15′. In addition, the data line 202 and the active layer 236 areetched by the dry etching of the passivation film 248. The gateinsulating layer 230 is exposed at the bottom surface of the first sidecontact hole SC11′ and the second side contact holes SC12′ to SC15′.

[0065] Then, as shown in FIG. 10C, by patterning a pixel electrode 214on the surface of the resultant structure, the pixel electrode 214 iselectrically contacted to the side of the data line 202 and physicallycontacted to the surface of the exposed gate insulating layer 230through the first side contact SC11 and through the second side contactsSC12 to SC15. Patterning of the pixel electrode 214 is performedsimultaneously while patterning the pixel electrode 214 of a unit pixeland a transparent conductive material, such as ITO, is applied to thepixel electrode 214.

[0066] Because the first side contact SC11 has a wider area than thoseof the plurality of the second side contacts SC12 to SC15, physicaladhering force of the pixel electrode 214 and the gate insulating layer230 is strengthened by securing a wide contact area between the pixelelectrode 214 and the gate insulating layer 230 having good interfacialadhering characteristics. Further, because the second side contacts SC12to SC15 are separated at a certain intervals and have an area smallerthan that of the first side contact SC11, electrical contact resistanceis reduced by securing a side contact area of the data line 202 and thepixel electrode 214. Also, in a probe inspection, needles are contactedto the first side contact SC11 having an area wider than those of thesecond side contacts SC12 to SC15. Accordingly, the alignment margin ofthe needles and the first side contact SC11 is secured. Unlike therelated art, it is possible to prevent the occurrence of scratches onthe surface of the data pad region caused by sliding of the needles dueto misalignment. Accordingly, damage to the needles can be prevented.

[0067] The bottom surface of the first side contact SC11 has an areawider than those of the second side contacts SC12 to SC15. Thus, thedata pad 214 is widely secured to an area contacting to the gateinsulating layer 230 made of SiNx or SiOx having good interfacialadhering characteristics. Because physical adhering force of the pixelelectrode 214 is strengthened, unlike the related art, it is possible toprevent the pixel electrode 214 from separating from the passivationfilm 248.

[0068] After the liquid crystal display panel is fabricated, when a TABdefect occurs in a module process for electrically contacting a datadriver integrated circuit to the data pad region by a TAB(tape-automated bonding) method, it is possible to prevent the pixelelectrode 214 from being separated partly or wholly from the passivationfilm 248 since the adhesion of the pixel electrode 214 is stronger tothe gate insulating layer 210 than to the defective TAB. Further, whenthe defective TAB is detached from the data pad region, it is alsopossible to prevent the pixel electrode 214 and the passivation film 248from being separated from the active layer 236.

[0069]FIG. 11 is an exemplary view illustrating a section of a data padregion of a liquid crystal display penal in accordance with a secondembodiment of the present invention. As shown in FIG. 11, data lines 302and 302+1 are vertically arranged at specified intervals, and data pads315A and 315B are electrically connected to the data lines 302 and302+1. Two first side contacts SC21 and SC22 are respectively formed atthe central portion of the data pads 315A and 315B. A plurality ofsecond side contacts SC22 to SC25 having an area smaller than that ofthe first side contacts SC21 and SC22 are respectively formed at the topend and the bottom end of the data pads 315A and 315B so as to beseparated from each other at specified intervals. In the data pad regionof the liquid crystal display panel in accordance with the secondembodiment of the present invention, the data pad region of the liquidcrystal display panel includes two first side contacts SC21 and SC31having an area wider than those of the plurality of the second sidecontacts SC22 to SC25. However, it is also possible to form more firstside contacts (not less than two) in consideration of a physical contactarea and an electrical contact area of the films constructing the datapads 315A to 315B.

[0070] In comparison with the first embodiment of the present invention,the second embodiment of the invention is different in that the data padregion of the liquid crystal display panel of the second embodiment ofthe present invention includes two first side contacts SC21 and SC31having an area wider than those of the plurality of the second sidecontacts SC22 to SC25. Accordingly, in the data pad region of the liquidcrystal display panel in accordance with the second embodiment of thepresent invention, a physical contact area of the films supporting thedata pads 315A and 315B through the two first side contacts SC21 andSC31 is secured. Further, there is more increased side contact area inthe films supporting the data pads 315A and 315B in comparison with thefirst embodiment of the present invention such that electrical contactresistance can be further reduced.

[0071]FIG. 12 is an exemplary view illustrating a section of a data padregion of a liquid crystal display penal in accordance with a thirdembodiment of the present invention. FIG. 12 has a similar constructionto FIG. 10C except that FIG. 12 has a triple deposition structure of aSiNx film 247/BCB film 248/SiNx film 249 as the passivation film 348.FIG. 12 has the same parts that have the same reference numerals as inFIG. 10.

[0072] In the related art, although the triple deposition structure of aSiNx film 247/BCB film 248/SiNx film 249 is applied as the passivationfilm 348 to improve interfacial adhering characteristics, when adefective TAB is detached from the data pad region, the pixel electrode214 and the SiNx film 249 may be separated from the BCB film 248. Inaddition, the pixel electrode 214, the SiNx film 249 and the BCB film248 may be separated from the SiNx film 247 by being adhered to thedefective TAB. Thus, interfacial adhering characteristics is notactually improved on the data pad region.

[0073] However, in the data pad region of the liquid crystal displaypanel in accordance with the third embodiment of the present invention,on the bottom surface of the first side contact SC11 having an areawider than those of the plurality of the second side contacts SC12 toSC15, because the pixel electrode 214 is contacted to the gateinsulating layer 230 made of SiNx or SiOx having good interfacialadhering characteristics, physical adhering force of the pixel electrode214 is strengthened. Accordingly, as described above, when a defectiveTAB is detached from the data pad region, it is possible to prevent thepixel electrode 214 and the SiNx film 249 from being separated from theBCB film 248 since the pixel electrode 214 adheres to the defective TAB.In addition, it is possible to prevent the pixel electrode 214, the SiNxfilm 249 and the BCB film 248 from being separated from the SiNx film247. Thus, interfacial adhering characteristics are improved by usingthe triple deposition structure of the SiNx film 247/BCB film 248/SiNxfilm 249 as the passivation film 348.

[0074] As described above, in the data pad region of the liquid crystaldisplay device and the fabrication method thereof in accordance with thepresent invention, by forming the first side contact widely at thecentral portion of the data pad region, physical contact area of filmsconstructing the data pads can be secured. Further, by forming aplurality of the second side contacts having an area smaller than thatof the first side contact at the edge of the data pad region so as to beseparated from each other at certain intervals, electrical contact areaof films supporting the data pads can be secured. Accordingly, in themodule process of the liquid crystal display panel, when the TAB isdetached from the data pad region due to TAB defect, it is possible toprevent films formed on the data pad region from being separated suchthat defects in of the liquid crystal display panel can be reduced. Inaddition, by preventing electrical contact resistance increase on thedata pad region, picture quality lowering of the liquid crystal displaypanel can be prevented.

[0075] It will be apparent to those skilled in the art that variousmodifications and variations can be made in the data pad region ofliquid crystal display panel and fabricating method thereof of thepresent invention without departing from the spirit or scope of theinventions. Thus, it is intended that the present invention covers themodifications and variations of this invention provided they come withinthe scope of the appended claims and their equivalents.

What is claimed is:
 1. A data pad region of a liquid crystal displaypanel, comprising: a plurality of data lines vertically arranged atspecified intervals; a plurality of data pads respectively connected tothe data lines; at least one first side contact with a first area formedin each data pad; and at least one second side contact with a secondarea formed in each data pad, wherein the first area is larger than thesecond area.
 2. The data pad region of claim 1, wherein the first sidecontact is positioned in a central portion of the data pad.
 3. The datapad region of claim 2, wherein at least two second side contacts arerespectively formed at one end of each data pad and at the other end ofeach data pad.
 4. A method for fabricating a data pad region of a liquidcrystal display panel, comprising: forming a gate insulating layer, datalines and a passivation film in a data pad forming region of asubstrate; forming at least one first side contact hole with a firstarea at the central region of the data pad forming region and forming atleast two second side contact holes with a second area respectively atboth edges of the data pad forming region, wherein the first area islarger than the second area; and forming at least one first side contactelectrically connecting one of the data lines to a conductive layer atthe first side contact hole and forming at least one second side contactelectrically contacting the data line to the conductive layer at thesecond side contact hole by patterning a conductive material.
 5. Themethod of claim 4, wherein the passivation film is made of an organicmaterial.
 6. The method of claim 4, wherein the passivation film is madeof BCB (benzocyclobutene).
 7. The method of claim 4, wherein thepassivation film is formed as a triple deposition structure of SiNxfilm/BCB (benzocyclobutene) film/SiNx film.
 8. The method of claim 4,wherein the data line is made of Mo.
 9. The method of claim 4, whereinthe data line is etched by dry-etching.
 10. The method of claim 4,wherein the gate insulating layer is exposed at the bottom surfaces ofthe first side contact hole and the second side contact hole bydry-etching of the passivation film.
 11. A data pad region of a liquidcrystal display panel, comprising: a substrate; a gate insulating layer,data lines and a passivation film in a data pad forming region of thesubstrate, wherein the passivation film in the data pad forming regionincluding at least one first side contact hole with a first area and atleast one second side contact hole with a second area, wherein the firstarea is larger than the second area; and at least one first side contactelectrically connecting one of the data lines to a conductive layer atthe first side contact hole and at least one second side contactelectrically connecting the data line to the conductive layer at thesecond side contact hole.
 12. The data pad region of claim 11, whereinthe passivation film is made of an organic material.
 13. The data padregion of claim 11, wherein the passivation film is made of BCB(benzocyclobutene).
 14. The data pad region of claim 11, wherein thepassivation film is formed as a triple deposition structure of SiNxfilm/BCB (benzocyclobutene) film/SiNx film.
 15. The data pad region ofclaim 11, wherein the data line is made of Mo.
 16. A liquid crystaldisplay panel, comprising: a substrate having an image display regionwith unit pixels arranged in a matrix and a data pad region at theperiphery of the image display region, wherein the data pad regionincludes: a plurality of data lines vertically arranged at specifiedintervals; a plurality of data pads respectively connected to the datalines; at least one first side contact with a first area formed in eachdata pad; and at least one second side contact with a second area formedin each data pad, wherein the first area is larger than the second area.